In material handling systems, it is often desired to transfer articles from one vertical elevation to another, while in other systems it may be desired to elevate articles over an obstruction, such as an aisle, and then lower the article back to the original elevation on the other side of the obstruction.
It is known to utilize material handling systems that incorporate endless members, such as chains or cables, that are mounted for endless travel and to attach carriers or trays to the chain. In systems of this type, articles are introduced onto the carriers as the carriers move in an upward path and are subsequently discharged when the carriers are at a higher elevation in the upward path. However, problems have arisen in attempting to automatically discharge the articles as the carrier is moving upwardly. In U.S. Pat. No. 3,664,482 and 4,421,227, the carriers are formed with a plurality of spaced horizontal fingers which travel upwardly through spaces in a conveyor to lift an article from the conveyor. At an elevated position, the carrier is then tilted to a downwardly inclined position to enable the articles to slide from the carrier for discharge. However, systems of this type do not insure a positive discharge, for the articles, depending on their nature, may not fully slide from the carriers with the result that the articles may be carried around to the top of the conveying path and then dumped. As a further disadvantage, systems of this type are not versatile and can only discharge articles in a single direction, namely in the direction of tilt of the carrier.